Low-cost industrial by-products as precursors for LiFePO_4 synthesis

摘要

Nanostructured lithium iron phosphate is a promising alternative for the positive electrode of next generation Li-ion batteries. The cost of LiFePO_4 material can be reduced by employing alternative lowcost precursors. In this study, iron sulphate heptahydrate produced as a by-product of industrial processing was utilised in aerosol-assisted nanoparticle synthesis. Aqueous precursor solution droplets were heated to 800 ℃ in a laminar flow reactor to achieve formation of LiFePO_4 with crystallite and particle size of about 60 and 300 nm, respectively. High fraction of two polymorphs of LiFePO_4 was found in the product powder. The fraction of the olivine polymorph was found to increase under reducing reaction atmosphere, while greater abundance of the high-pressure polymorph was obtained with an iron rich precursor stoichiometry. Hence, it was shown that the low-cost precursors can be used in aerosol-assisted synthesis of LiFePO_4; and the product composition can be fine tuned to the requirements of the application by varying the process parameters.